lib/libfetch/http.c

   1 /*-
   2  * Copyright (c) 2000-2004 Dag-Erling Coïdan Smørgrav
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer
  10  *    in this position and unchanged.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * $FreeBSD: src/lib/libfetch/http.c,v 1.78 2007/05/08 19:28:03 des Exp $
  29  * $DragonFly: src/lib/libfetch/http.c,v 1.4 2007/08/05 21:48:12 swildner Exp $
  30  */
  31
  32 /*
  33  * The following copyright applies to the base64 code:
  34  *
  35  *-
  36  * Copyright 1997 Massachusetts Institute of Technology
  37  *
  38  * Permission to use, copy, modify, and distribute this software and
  39  * its documentation for any purpose and without fee is hereby
  40  * granted, provided that both the above copyright notice and this
  41  * permission notice appear in all copies, that both the above
  42  * copyright notice and this permission notice appear in all
  43  * supporting documentation, and that the name of M.I.T. not be used
  44  * in advertising or publicity pertaining to distribution of the
  45  * software without specific, written prior permission.  M.I.T. makes
  46  * no representations about the suitability of this software for any
  47  * purpose.  It is provided "as is" without express or implied
  48  * warranty.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
  51  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
  52  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  53  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
  54  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  55  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  56  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  57  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  58  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  59  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  60  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  */
  63
  64 #include <sys/param.h>
  65 #include <sys/socket.h>
  66
  67 #include <ctype.h>
  68 #include <err.h>
  69 #include <errno.h>
  70 #include <locale.h>
  71 #include <netdb.h>
  72 #include <stdarg.h>
  73 #include <stdio.h>
  74 #include <stdlib.h>
  75 #include <string.h>
  76 #include <time.h>
  77 #include <unistd.h>
  78
  79 #include <netinet/in.h>
  80 #include <netinet/tcp.h>
  81
  82 #include "fetch.h"
  83 #include "common.h"
  84 #include "httperr.h"
  85
  86 /* Maximum number of redirects to follow */
  87 #define MAX_REDIRECT 5
  88
  89 /* Symbolic names for reply codes we care about */
  90 #define HTTP_OK                 200
  91 #define HTTP_PARTIAL            206
  92 #define HTTP_MOVED_PERM         301
  93 #define HTTP_MOVED_TEMP         302
  94 #define HTTP_SEE_OTHER          303
  95 #define HTTP_TEMP_REDIRECT      307
  96 #define HTTP_NEED_AUTH          401
  97 #define HTTP_NEED_PROXY_AUTH    407
  98 #define HTTP_BAD_RANGE          416
  99 #define HTTP_PROTOCOL_ERROR     999
 100
 101 #define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
 102                             || (xyz) == HTTP_MOVED_TEMP \
 103                             || (xyz) == HTTP_TEMP_REDIRECT \
 104                             || (xyz) == HTTP_SEE_OTHER)
 105
 106 #define HTTP_ERROR(xyz) ((xyz) > 400 && (xyz) < 599)
 107
 108
 109 /*****************************************************************************
 110  * I/O functions for decoding chunked streams
 111  */
 112
 113 struct httpio
 114 {
 115         conn_t          *conn;          /* connection */
 116         int              chunked;       /* chunked mode */
 117         char            *buf;           /* chunk buffer */
 118         size_t           bufsize;       /* size of chunk buffer */
 119         ssize_t          buflen;        /* amount of data currently in buffer */
 120         int              bufpos;        /* current read offset in buffer */
 121         int              eof;           /* end-of-file flag */
 122         int              error;         /* error flag */
 123         size_t           chunksize;     /* remaining size of current chunk */
 124 #ifndef NDEBUG
 125         size_t           total;
 126 #endif
 127 };
 128
 129 /*
 130  * Get next chunk header
 131  */
 132 static int
 133 _http_new_chunk(struct httpio *io)
 134 {
 135         char *p;
 136
 137         if (_fetch_getln(io->conn) == -1)
 138                 return (-1);
 139
 140         if (io->conn->buflen < 2 || !isxdigit(*io->conn->buf))
 141                 return (-1);
 142
 143         for (p = io->conn->buf; *p && !isspace(*p); ++p) {
 144                 if (*p == ';')
 145                         break;
 146                 if (!isxdigit(*p))
 147                         return (-1);
 148                 if (isdigit(*p)) {
 149                         io->chunksize = io->chunksize * 16 +
 150                             *p - '0';
 151                 } else {
 152                         io->chunksize = io->chunksize * 16 +
 153                             10 + tolower(*p) - 'a';
 154                 }
 155         }
 156
 157 #ifndef NDEBUG
 158         if (fetchDebug) {
 159                 io->total += io->chunksize;
 160                 if (io->chunksize == 0)
 161                         fprintf(stderr, "%s(): end of last chunk\n", __func__);
 162                 else
 163                         fprintf(stderr, "%s(): new chunk: %lu (%lu)\n",
 164                             __func__, (unsigned long)io->chunksize,
 165                             (unsigned long)io->total);
 166         }
 167 #endif
 168
 169         return (io->chunksize);
 170 }
 171
 172 /*
 173  * Grow the input buffer to at least len bytes
 174  */
 175 static inline int
 176 _http_growbuf(struct httpio *io, size_t len)
 177 {
 178         char *tmp;
 179
 180         if (io->bufsize >= len)
 181                 return (0);
 182
 183         if ((tmp = realloc(io->buf, len)) == NULL)
 184                 return (-1);
 185         io->buf = tmp;
 186         io->bufsize = len;
 187         return (0);
 188 }
 189
 190 /*
 191  * Fill the input buffer, do chunk decoding on the fly
 192  */
 193 static int
 194 _http_fillbuf(struct httpio *io, size_t len)
 195 {
 196         if (io->error)
 197                 return (-1);
 198         if (io->eof)
 199                 return (0);
 200
 201         if (io->chunked == 0) {
 202                 if (_http_growbuf(io, len) == -1)
 203                         return (-1);
 204                 if ((io->buflen = _fetch_read(io->conn, io->buf, len)) == -1) {
 205                         io->error = 1;
 206                         return (-1);
 207                 }
 208                 io->bufpos = 0;
 209                 return (io->buflen);
 210         }
 211
 212         if (io->chunksize == 0) {
 213                 switch (_http_new_chunk(io)) {
 214                 case -1:
 215                         io->error = 1;
 216                         return (-1);
 217                 case 0:
 218                         io->eof = 1;
 219                         return (0);
 220                 }
 221         }
 222
 223         if (len > io->chunksize)
 224                 len = io->chunksize;
 225         if (_http_growbuf(io, len) == -1)
 226                 return (-1);
 227         if ((io->buflen = _fetch_read(io->conn, io->buf, len)) == -1) {
 228                 io->error = 1;
 229                 return (-1);
 230         }
 231         io->chunksize -= io->buflen;
 232
 233         if (io->chunksize == 0) {
 234                 char endl[2];
 235
 236                 if (_fetch_read(io->conn, endl, 2) != 2 ||
 237                     endl[0] != '\r' || endl[1] != '\n')
 238                         return (-1);
 239         }
 240
 241         io->bufpos = 0;
 242
 243         return (io->buflen);
 244 }
 245
 246 /*
 247  * Read function
 248  */
 249 static int
 250 _http_readfn(void *v, char *buf, int len)
 251 {
 252         struct httpio *io = (struct httpio *)v;
 253         int l, pos;
 254
 255         if (io->error)
 256                 return (-1);
 257         if (io->eof)
 258                 return (0);
 259
 260         for (pos = 0; len > 0; pos += l, len -= l) {
 261                 /* empty buffer */
 262                 if (!io->buf || io->bufpos == io->buflen)
 263                         if (_http_fillbuf(io, len) < 1)
 264                                 break;
 265                 l = io->buflen - io->bufpos;
 266                 if (len < l)
 267                         l = len;
 268                 bcopy(io->buf + io->bufpos, buf + pos, l);
 269                 io->bufpos += l;
 270         }
 271
 272         if (!pos && io->error)
 273                 return (-1);
 274         return (pos);
 275 }
 276
 277 /*
 278  * Write function
 279  */
 280 static int
 281 _http_writefn(void *v, const char *buf, int len)
 282 {
 283         struct httpio *io = (struct httpio *)v;
 284
 285         return (_fetch_write(io->conn, buf, len));
 286 }
 287
 288 /*
 289  * Close function
 290  */
 291 static int
 292 _http_closefn(void *v)
 293 {
 294         struct httpio *io = (struct httpio *)v;
 295         int r;
 296
 297         r = _fetch_close(io->conn);
 298         if (io->buf)
 299                 free(io->buf);
 300         free(io);
 301         return (r);
 302 }
 303
 304 /*
 305  * Wrap a file descriptor up
 306  */
 307 static FILE *
 308 _http_funopen(conn_t *conn, int chunked)
 309 {
 310         struct httpio *io;
 311         FILE *f;
 312
 313         if ((io = calloc(1, sizeof(*io))) == NULL) {
 314                 _fetch_syserr();
 315                 return (NULL);
 316         }
 317         io->conn = conn;
 318         io->chunked = chunked;
 319         f = funopen(io, _http_readfn, _http_writefn, NULL, _http_closefn);
 320         if (f == NULL) {
 321                 _fetch_syserr();
 322                 free(io);
 323                 return (NULL);
 324         }
 325         return (f);
 326 }
 327
 328
 329 /*****************************************************************************
 330  * Helper functions for talking to the server and parsing its replies
 331  */
 332
 333 /* Header types */
 334 typedef enum {
 335         hdr_syserror = -2,
 336         hdr_error = -1,
 337         hdr_end = 0,
 338         hdr_unknown = 1,
 339         hdr_content_length,
 340         hdr_content_range,
 341         hdr_last_modified,
 342         hdr_location,
 343         hdr_transfer_encoding,
 344         hdr_www_authenticate
 345 } hdr_t;
 346
 347 /* Names of interesting headers */
 348 static struct {
 349         hdr_t            num;
 350         const char      *name;
 351 } hdr_names[] = {
 352         { hdr_content_length,           "Content-Length" },
 353         { hdr_content_range,            "Content-Range" },
 354         { hdr_last_modified,            "Last-Modified" },
 355         { hdr_location,                 "Location" },
 356         { hdr_transfer_encoding,        "Transfer-Encoding" },
 357         { hdr_www_authenticate,         "WWW-Authenticate" },
 358         { hdr_unknown,                  NULL },
 359 };
 360
 361 /*
 362  * Send a formatted line; optionally echo to terminal
 363  */
 364 static int
 365 _http_cmd(conn_t *conn, const char *fmt, ...)
 366 {
 367         va_list ap;
 368         size_t len;
 369         char *msg;
 370         int r;
 371
 372         va_start(ap, fmt);
 373         len = vasprintf(&msg, fmt, ap);
 374         va_end(ap);
 375
 376         if (msg == NULL) {
 377                 errno = ENOMEM;
 378                 _fetch_syserr();
 379                 return (-1);
 380         }
 381
 382         r = _fetch_putln(conn, msg, len);
 383         free(msg);
 384
 385         if (r == -1) {
 386                 _fetch_syserr();
 387                 return (-1);
 388         }
 389
 390         return (0);
 391 }
 392
 393 /*
 394  * Get and parse status line
 395  */
 396 static int
 397 _http_get_reply(conn_t *conn)
 398 {
 399         char *p;
 400
 401         if (_fetch_getln(conn) == -1)
 402                 return (-1);
 403         /*
 404          * A valid status line looks like "HTTP/m.n xyz reason" where m
 405          * and n are the major and minor protocol version numbers and xyz
 406          * is the reply code.
 407          * Unfortunately, there are servers out there (NCSA 1.5.1, to name
 408          * just one) that do not send a version number, so we can't rely
 409          * on finding one, but if we do, insist on it being 1.0 or 1.1.
 410          * We don't care about the reason phrase.
 411          */
 412         if (strncmp(conn->buf, "HTTP", 4) != 0)
 413                 return (HTTP_PROTOCOL_ERROR);
 414         p = conn->buf + 4;
 415         if (*p == '/') {
 416                 if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
 417                         return (HTTP_PROTOCOL_ERROR);
 418                 p += 4;
 419         }
 420         if (*p != ' ' || !isdigit(p[1]) || !isdigit(p[2]) || !isdigit(p[3]))
 421                 return (HTTP_PROTOCOL_ERROR);
 422
 423         conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
 424         return (conn->err);
 425 }
 426
 427 /*
 428  * Check a header; if the type matches the given string, return a pointer
 429  * to the beginning of the value.
 430  */
 431 static const char *
 432 _http_match(const char *str, const char *hdr)
 433 {
 434         while (*str && *hdr && tolower(*str++) == tolower(*hdr++))
 435                 /* nothing */;
 436         if (*str || *hdr != ':')
 437                 return (NULL);
 438         while (*hdr && isspace(*++hdr))
 439                 /* nothing */;
 440         return (hdr);
 441 }
 442
 443 /*
 444  * Get the next header and return the appropriate symbolic code.
 445  */
 446 static hdr_t
 447 _http_next_header(conn_t *conn, const char **p)
 448 {
 449         int i;
 450
 451         if (_fetch_getln(conn) == -1)
 452                 return (hdr_syserror);
 453         while (conn->buflen && isspace(conn->buf[conn->buflen - 1]))
 454                 conn->buflen--;
 455         conn->buf[conn->buflen] = '\0';
 456         if (conn->buflen == 0)
 457                 return (hdr_end);
 458         /*
 459          * We could check for malformed headers but we don't really care.
 460          * A valid header starts with a token immediately followed by a
 461          * colon; a token is any sequence of non-control, non-whitespace
 462          * characters except "()<>@,;:\\\"{}".
 463          */
 464         for (i = 0; hdr_names[i].num != hdr_unknown; i++)
 465                 if ((*p = _http_match(hdr_names[i].name, conn->buf)) != NULL)
 466                         return (hdr_names[i].num);
 467         return (hdr_unknown);
 468 }
 469
 470 /*
 471  * Parse a last-modified header
 472  */
 473 static int
 474 _http_parse_mtime(const char *p, time_t *mtime)
 475 {
 476         char locale[64], *r;
 477         struct tm tm;
 478
 479         strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
 480         setlocale(LC_TIME, "C");
 481         r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
 482         /* XXX should add support for date-2 and date-3 */
 483         setlocale(LC_TIME, locale);
 484         if (r == NULL)
 485                 return (-1);
 486         DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
 487                   "%02d:%02d:%02d]\n",
 488                   tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 489                   tm.tm_hour, tm.tm_min, tm.tm_sec));
 490         *mtime = timegm(&tm);
 491         return (0);
 492 }
 493
 494 /*
 495  * Parse a content-length header
 496  */
 497 static int
 498 _http_parse_length(const char *p, off_t *length)
 499 {
 500         off_t len;
 501
 502         for (len = 0; *p && isdigit(*p); ++p)
 503                 len = len * 10 + (*p - '0');
 504         if (*p)
 505                 return (-1);
 506         DEBUG(fprintf(stderr, "content length: [%lld]\n",
 507             (long long)len));
 508         *length = len;
 509         return (0);
 510 }
 511
 512 /*
 513  * Parse a content-range header
 514  */
 515 static int
 516 _http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
 517 {
 518         off_t first, last, len;
 519
 520         if (strncasecmp(p, "bytes ", 6) != 0)
 521                 return (-1);
 522         p += 6;
 523         if (*p == '*') {
 524                 first = last = -1;
 525                 ++p;
 526         } else {
 527                 for (first = 0; *p && isdigit(*p); ++p)
 528                         first = first * 10 + *p - '0';
 529                 if (*p != '-')
 530                         return (-1);
 531                 for (last = 0, ++p; *p && isdigit(*p); ++p)
 532                         last = last * 10 + *p - '0';
 533         }
 534         if (first > last || *p != '/')
 535                 return (-1);
 536         for (len = 0, ++p; *p && isdigit(*p); ++p)
 537                 len = len * 10 + *p - '0';
 538         if (*p || len < last - first + 1)
 539                 return (-1);
 540         if (first == -1) {
 541                 DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
 542                     (long long)len));
 543                 *length = 0;
 544         } else {
 545                 DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
 546                     (long long)first, (long long)last, (long long)len));
 547                 *length = last - first + 1;
 548         }
 549         *offset = first;
 550         *size = len;
 551         return (0);
 552 }
 553
 554
 555 /*****************************************************************************
 556  * Helper functions for authorization
 557  */
 558
 559 /*
 560  * Base64 encoding
 561  */
 562 static char *
 563 _http_base64(const char *src)
 564 {
 565         static const char base64[] =
 566             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 567             "abcdefghijklmnopqrstuvwxyz"
 568             "0123456789+/";
 569         char *str, *dst;
 570         size_t l;
 571         int t, r;
 572
 573         l = strlen(src);
 574         if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
 575                 return (NULL);
 576         dst = str;
 577         r = 0;
 578
 579         while (l >= 3) {
 580                 t = (src[0] << 16) | (src[1] << 8) | src[2];
 581                 dst[0] = base64[(t >> 18) & 0x3f];
 582                 dst[1] = base64[(t >> 12) & 0x3f];
 583                 dst[2] = base64[(t >> 6) & 0x3f];
 584                 dst[3] = base64[(t >> 0) & 0x3f];
 585                 src += 3; l -= 3;
 586                 dst += 4; r += 4;
 587         }
 588
 589         switch (l) {
 590         case 2:
 591                 t = (src[0] << 16) | (src[1] << 8);
 592                 dst[0] = base64[(t >> 18) & 0x3f];
 593                 dst[1] = base64[(t >> 12) & 0x3f];
 594                 dst[2] = base64[(t >> 6) & 0x3f];
 595                 dst[3] = '=';
 596                 dst += 4;
 597                 r += 4;
 598                 break;
 599         case 1:
 600                 t = src[0] << 16;
 601                 dst[0] = base64[(t >> 18) & 0x3f];
 602                 dst[1] = base64[(t >> 12) & 0x3f];
 603                 dst[2] = dst[3] = '=';
 604                 dst += 4;
 605                 r += 4;
 606                 break;
 607         case 0:
 608                 break;
 609         }
 610
 611         *dst = 0;
 612         return (str);
 613 }
 614
 615 /*
 616  * Encode username and password
 617  */
 618 static int
 619 _http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
 620 {
 621         char *upw, *auth;
 622         int r;
 623
 624         DEBUG(fprintf(stderr, "usr: [%s]\n", usr));
 625         DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
 626         if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
 627                 return (-1);
 628         auth = _http_base64(upw);
 629         free(upw);
 630         if (auth == NULL)
 631                 return (-1);
 632         r = _http_cmd(conn, "%s: Basic %s", hdr, auth);
 633         free(auth);
 634         return (r);
 635 }
 636
 637 /*
 638  * Send an authorization header
 639  */
 640 static int
 641 _http_authorize(conn_t *conn, const char *hdr, const char *p)
 642 {
 643         /* basic authorization */
 644         if (strncasecmp(p, "basic:", 6) == 0) {
 645                 char *user, *pwd, *str;
 646                 int r;
 647
 648                 /* skip realm */
 649                 for (p += 6; *p && *p != ':'; ++p)
 650                         /* nothing */ ;
 651                 if (!*p || strchr(++p, ':') == NULL)
 652                         return (-1);
 653                 if ((str = strdup(p)) == NULL)
 654                         return (-1); /* XXX */
 655                 user = str;
 656                 pwd = strchr(str, ':');
 657                 *pwd++ = '\0';
 658                 r = _http_basic_auth(conn, hdr, user, pwd);
 659                 free(str);
 660                 return (r);
 661         }
 662         return (-1);
 663 }
 664
 665
 666 /*****************************************************************************
 667  * Helper functions for connecting to a server or proxy
 668  */
 669
 670 /*
 671  * Connect to the correct HTTP server or proxy.
 672  */
 673 static conn_t *
 674 _http_connect(struct url *URL, struct url *purl, const char *flags)
 675 {
 676         conn_t *conn;
 677         int verbose;
 678         int af, val;
 679
 680 #ifdef INET6
 681         af = AF_UNSPEC;
 682 #else
 683         af = AF_INET;
 684 #endif
 685
 686         verbose = CHECK_FLAG('v');
 687         if (CHECK_FLAG('4'))
 688                 af = AF_INET;
 689 #ifdef INET6
 690         else if (CHECK_FLAG('6'))
 691                 af = AF_INET6;
 692 #endif
 693
 694         if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
 695                 URL = purl;
 696         } else if (strcasecmp(URL->scheme, SCHEME_FTP) == 0) {
 697                 /* can't talk http to an ftp server */
 698                 /* XXX should set an error code */
 699                 return (NULL);
 700         }
 701
 702         if ((conn = _fetch_connect(URL->host, URL->port, af, verbose)) == NULL)
 703                 /* _fetch_connect() has already set an error code */
 704                 return (NULL);
 705         if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
 706             _fetch_ssl(conn, verbose) == -1) {
 707                 _fetch_close(conn);
 708                 /* grrr */
 709                 errno = EAUTH;
 710                 _fetch_syserr();
 711                 return (NULL);
 712         }
 713
 714         val = 1;
 715         setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
 716
 717         return (conn);
 718 }
 719
 720 static struct url *
 721 _http_get_proxy(const char *flags)
 722 {
 723         struct url *purl;
 724         char *p;
 725
 726         if (flags != NULL && strchr(flags, 'd') != NULL)
 727                 return (NULL);
 728         if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
 729             *p && (purl = fetchParseURL(p))) {
 730                 if (!*purl->scheme)
 731                         strcpy(purl->scheme, SCHEME_HTTP);
 732                 if (!purl->port)
 733                         purl->port = _fetch_default_proxy_port(purl->scheme);
 734                 if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
 735                         return (purl);
 736                 fetchFreeURL(purl);
 737         }
 738         return (NULL);
 739 }
 740
 741 static void
 742 _http_print_html(FILE *out, FILE *in)
 743 {
 744         size_t len;
 745         char *line, *p, *q;
 746         int comment, tag;
 747
 748         comment = tag = 0;
 749         while ((line = fgetln(in, &len)) != NULL) {
 750                 while (len && isspace(line[len - 1]))
 751                         --len;
 752                 for (p = q = line; q < line + len; ++q) {
 753                         if (comment && *q == '-') {
 754                                 if (q + 2 < line + len &&
 755                                     strcmp(q, "-->") == 0) {
 756                                         tag = comment = 0;
 757                                         q += 2;
 758                                 }
 759                         } else if (tag && !comment && *q == '>') {
 760                                 p = q + 1;
 761                                 tag = 0;
 762                         } else if (!tag && *q == '<') {
 763                                 if (q > p)
 764                                         fwrite(p, q - p, 1, out);
 765                                 tag = 1;
 766                                 if (q + 3 < line + len &&
 767                                     strcmp(q, "<!--") == 0) {
 768                                         comment = 1;
 769                                         q += 3;
 770                                 }
 771                         }
 772                 }
 773                 if (!tag && q > p)
 774                         fwrite(p, q - p, 1, out);
 775                 fputc('\n', out);
 776         }
 777 }
 778
 779
 780 /*****************************************************************************
 781  * Core
 782  */
 783
 784 /*
 785  * Send a request and process the reply
 786  *
 787  * XXX This function is way too long, the do..while loop should be split
 788  * XXX off into a separate function.
 789  */
 790 FILE *
 791 _http_request(struct url *URL, const char *op, struct url_stat *us,
 792     struct url *purl, const char *flags)
 793 {
 794         conn_t *conn;
 795         struct url *url, *new;
 796         int chunked, direct, need_auth, noredirect, verbose;
 797         int e, i, n, val;
 798         off_t offset, clength, length, size;
 799         time_t mtime;
 800         const char *p;
 801         FILE *f;
 802         hdr_t h;
 803         char hbuf[MAXHOSTNAMELEN + 7], *host;
 804
 805         direct = CHECK_FLAG('d');
 806         noredirect = CHECK_FLAG('A');
 807         verbose = CHECK_FLAG('v');
 808
 809         if (direct && purl) {
 810                 fetchFreeURL(purl);
 811                 purl = NULL;
 812         }
 813
 814         /* try the provided URL first */
 815         url = URL;
 816
 817         /* if the A flag is set, we only get one try */
 818         n = noredirect ? 1 : MAX_REDIRECT;
 819         i = 0;
 820
 821         e = HTTP_PROTOCOL_ERROR;
 822         need_auth = 0;
 823         do {
 824                 new = NULL;
 825                 chunked = 0;
 826                 offset = 0;
 827                 clength = -1;
 828                 length = -1;
 829                 size = -1;
 830                 mtime = 0;
 831
 832                 /* check port */
 833                 if (!url->port)
 834                         url->port = _fetch_default_port(url->scheme);
 835
 836                 /* were we redirected to an FTP URL? */
 837                 if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
 838                         if (strcmp(op, "GET") == 0)
 839                                 return (_ftp_request(url, "RETR", us, purl, flags));
 840                         else if (strcmp(op, "HEAD") == 0)
 841                                 return (_ftp_request(url, "STAT", us, purl, flags));
 842                 }
 843
 844                 /* connect to server or proxy */
 845                 if ((conn = _http_connect(url, purl, flags)) == NULL)
 846                         goto ouch;
 847
 848                 host = url->host;
 849 #ifdef INET6
 850                 if (strchr(url->host, ':')) {
 851                         snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
 852                         host = hbuf;
 853                 }
 854 #endif
 855                 if (url->port != _fetch_default_port(url->scheme)) {
 856                         if (host != hbuf) {
 857                                 strcpy(hbuf, host);
 858                                 host = hbuf;
 859                         }
 860                         snprintf(hbuf + strlen(hbuf),
 861                             sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
 862                 }
 863
 864                 /* send request */
 865                 if (verbose)
 866                         _fetch_info("requesting %s://%s%s",
 867                             url->scheme, host, url->doc);
 868                 if (purl) {
 869                         _http_cmd(conn, "%s %s://%s%s HTTP/1.1",
 870                             op, url->scheme, host, url->doc);
 871                 } else {
 872                         _http_cmd(conn, "%s %s HTTP/1.1",
 873                             op, url->doc);
 874                 }
 875
 876                 /* virtual host */
 877                 _http_cmd(conn, "Host: %s", host);
 878
 879                 /* proxy authorization */
 880                 if (purl) {
 881                         if (*purl->user || *purl->pwd)
 882                                 _http_basic_auth(conn, "Proxy-Authorization",
 883                                     purl->user, purl->pwd);
 884                         else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL && *p != '\0')
 885                                 _http_authorize(conn, "Proxy-Authorization", p);
 886                 }
 887
 888                 /* server authorization */
 889                 if (need_auth || *url->user || *url->pwd) {
 890                         if (*url->user || *url->pwd)
 891                                 _http_basic_auth(conn, "Authorization", url->user, url->pwd);
 892                         else if ((p = getenv("HTTP_AUTH")) != NULL && *p != '\0')
 893                                 _http_authorize(conn, "Authorization", p);
 894                         else if (fetchAuthMethod && fetchAuthMethod(url) == 0) {
 895                                 _http_basic_auth(conn, "Authorization", url->user, url->pwd);
 896                         } else {
 897                                 _http_seterr(HTTP_NEED_AUTH);
 898                                 goto ouch;
 899                         }
 900                 }
 901
 902                 /* other headers */
 903                 if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
 904                         if (strcasecmp(p, "auto") == 0)
 905                                 _http_cmd(conn, "Referer: %s://%s%s",
 906                                     url->scheme, host, url->doc);
 907                         else
 908                                 _http_cmd(conn, "Referer: %s", p);
 909                 }
 910                 if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
 911                         _http_cmd(conn, "User-Agent: %s", p);
 912                 else
 913                         _http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
 914                 if (url->offset > 0)
 915                         _http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
 916                 _http_cmd(conn, "Connection: close");
 917                 _http_cmd(conn, "");
 918
 919                 /*
 920                  * Force the queued request to be dispatched.  Normally, one
 921                  * would do this with shutdown(2) but squid proxies can be
 922                  * configured to disallow such half-closed connections.  To
 923                  * be compatible with such configurations, fiddle with socket
 924                  * options to force the pending data to be written.
 925                  */
 926                 val = 0;
 927                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
 928                            sizeof(val));
 929                 val = 1;
 930                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
 931                            sizeof(val));
 932
 933                 /* get reply */
 934                 switch (_http_get_reply(conn)) {
 935                 case HTTP_OK:
 936                 case HTTP_PARTIAL:
 937                         /* fine */
 938                         break;
 939                 case HTTP_MOVED_PERM:
 940                 case HTTP_MOVED_TEMP:
 941                 case HTTP_SEE_OTHER:
 942                         /*
 943                          * Not so fine, but we still have to read the
 944                          * headers to get the new location.
 945                          */
 946                         break;
 947                 case HTTP_NEED_AUTH:
 948                         if (need_auth) {
 949                                 /*
 950                                  * We already sent out authorization code,
 951                                  * so there's nothing more we can do.
 952                                  */
 953                                 _http_seterr(conn->err);
 954                                 goto ouch;
 955                         }
 956                         /* try again, but send the password this time */
 957                         if (verbose)
 958                                 _fetch_info("server requires authorization");
 959                         break;
 960                 case HTTP_NEED_PROXY_AUTH:
 961                         /*
 962                          * If we're talking to a proxy, we already sent
 963                          * our proxy authorization code, so there's
 964                          * nothing more we can do.
 965                          */
 966                         _http_seterr(conn->err);
 967                         goto ouch;
 968                 case HTTP_BAD_RANGE:
 969                         /*
 970                          * This can happen if we ask for 0 bytes because
 971                          * we already have the whole file.  Consider this
 972                          * a success for now, and check sizes later.
 973                          */
 974                         break;
 975                 case HTTP_PROTOCOL_ERROR:
 976                         /* fall through */
 977                 case -1:
 978                         _fetch_syserr();
 979                         goto ouch;
 980                 default:
 981                         _http_seterr(conn->err);
 982                         if (!verbose)
 983                                 goto ouch;
 984                         /* fall through so we can get the full error message */
 985                 }
 986
 987                 /* get headers */
 988                 do {
 989                         switch ((h = _http_next_header(conn, &p))) {
 990                         case hdr_syserror:
 991                                 _fetch_syserr();
 992                                 goto ouch;
 993                         case hdr_error:
 994                                 _http_seterr(HTTP_PROTOCOL_ERROR);
 995                                 goto ouch;
 996                         case hdr_content_length:
 997                                 _http_parse_length(p, &clength);
 998                                 break;
 999                         case hdr_content_range:
1000                                 _http_parse_range(p, &offset, &length, &size);
1001                                 break;
1002                         case hdr_last_modified:
1003                                 _http_parse_mtime(p, &mtime);
1004                                 break;
1005                         case hdr_location:
1006                                 if (!HTTP_REDIRECT(conn->err))
1007                                         break;
1008                                 if (new)
1009                                         free(new);
1010                                 if (verbose)
1011                                         _fetch_info("%d redirect to %s", conn->err, p);
1012                                 if (*p == '/')
1013                                         /* absolute path */
1014                                         new = fetchMakeURL(url->scheme, url->host, url->port, p,
1015                                             url->user, url->pwd);
1016                                 else
1017                                         new = fetchParseURL(p);
1018                                 if (new == NULL) {
1019                                         /* XXX should set an error code */
1020                                         DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1021                                         goto ouch;
1022                                 }
1023                                 if (!*new->user && !*new->pwd) {
1024                                         strcpy(new->user, url->user);
1025                                         strcpy(new->pwd, url->pwd);
1026                                 }
1027                                 new->offset = url->offset;
1028                                 new->length = url->length;
1029                                 break;
1030                         case hdr_transfer_encoding:
1031                                 /* XXX weak test*/
1032                                 chunked = (strcasecmp(p, "chunked") == 0);
1033                                 break;
1034                         case hdr_www_authenticate:
1035                                 if (conn->err != HTTP_NEED_AUTH)
1036                                         break;
1037                                 /* if we were smarter, we'd check the method and realm */
1038                                 break;
1039                         case hdr_end:
1040                                 /* fall through */
1041                         case hdr_unknown:
1042                                 /* ignore */
1043                                 break;
1044                         }
1045                 } while (h > hdr_end);
1046
1047                 /* we need to provide authentication */
1048                 if (conn->err == HTTP_NEED_AUTH) {
1049                         e = conn->err;
1050                         need_auth = 1;
1051                         _fetch_close(conn);
1052                         conn = NULL;
1053                         continue;
1054                 }
1055
1056                 /* requested range not satisfiable */
1057                 if (conn->err == HTTP_BAD_RANGE) {
1058                         if (url->offset == size && url->length == 0) {
1059                                 /* asked for 0 bytes; fake it */
1060                                 offset = url->offset;
1061                                 conn->err = HTTP_OK;
1062                                 break;
1063                         } else {
1064                                 _http_seterr(conn->err);
1065                                 goto ouch;
1066                         }
1067                 }
1068
1069                 /* we have a hit or an error */
1070                 if (conn->err == HTTP_OK || conn->err == HTTP_PARTIAL || HTTP_ERROR(conn->err))
1071                         break;
1072
1073                 /* all other cases: we got a redirect */
1074                 e = conn->err;
1075                 need_auth = 0;
1076                 _fetch_close(conn);
1077                 conn = NULL;
1078                 if (!new) {
1079                         DEBUG(fprintf(stderr, "redirect with no new location\n"));
1080                         break;
1081                 }
1082                 if (url != URL)
1083                         fetchFreeURL(url);
1084                 url = new;
1085         } while (++i < n);
1086
1087         /* we failed, or ran out of retries */
1088         if (conn == NULL) {
1089                 _http_seterr(e);
1090                 goto ouch;
1091         }
1092
1093         DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1094                   " size %lld, clength %lld\n",
1095                   (long long)offset, (long long)length,
1096                   (long long)size, (long long)clength));
1097
1098         /* check for inconsistencies */
1099         if (clength != -1 && length != -1 && clength != length) {
1100                 _http_seterr(HTTP_PROTOCOL_ERROR);
1101                 goto ouch;
1102         }
1103         if (clength == -1)
1104                 clength = length;
1105         if (clength != -1)
1106                 length = offset + clength;
1107         if (length != -1 && size != -1 && length != size) {
1108                 _http_seterr(HTTP_PROTOCOL_ERROR);
1109                 goto ouch;
1110         }
1111         if (size == -1)
1112                 size = length;
1113
1114         /* fill in stats */
1115         if (us) {
1116                 us->size = size;
1117                 us->atime = us->mtime = mtime;
1118         }
1119
1120         /* too far? */
1121         if (URL->offset > 0 && offset > URL->offset) {
1122                 _http_seterr(HTTP_PROTOCOL_ERROR);
1123                 goto ouch;
1124         }
1125
1126         /* report back real offset and size */
1127         URL->offset = offset;
1128         URL->length = clength;
1129
1130         /* wrap it up in a FILE */
1131         if ((f = _http_funopen(conn, chunked)) == NULL) {
1132                 _fetch_syserr();
1133                 goto ouch;
1134         }
1135
1136         if (url != URL)
1137                 fetchFreeURL(url);
1138         if (purl)
1139                 fetchFreeURL(purl);
1140
1141         if (HTTP_ERROR(conn->err)) {
1142                 _http_print_html(stderr, f);
1143                 fclose(f);
1144                 f = NULL;
1145         }
1146
1147         return (f);
1148
1149 ouch:
1150         if (url != URL)
1151                 fetchFreeURL(url);
1152         if (purl)
1153                 fetchFreeURL(purl);
1154         if (conn != NULL)
1155                 _fetch_close(conn);
1156         return (NULL);
1157 }
1158
1159
1160 /*****************************************************************************
1161  * Entry points
1162  */
1163
1164 /*
1165  * Retrieve and stat a file by HTTP
1166  */
1167 FILE *
1168 fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1169 {
1170         return (_http_request(URL, "GET", us, _http_get_proxy(flags), flags));
1171 }
1172
1173 /*
1174  * Retrieve a file by HTTP
1175  */
1176 FILE *
1177 fetchGetHTTP(struct url *URL, const char *flags)
1178 {
1179         return (fetchXGetHTTP(URL, NULL, flags));
1180 }
1181
1182 /*
1183  * Store a file by HTTP
1184  */
1185 FILE *
1186 fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
1187 {
1188         warnx("fetchPutHTTP(): not implemented");
1189         return (NULL);
1190 }
1191
1192 /*
1193  * Get an HTTP document's metadata
1194  */
1195 int
1196 fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
1197 {
1198         FILE *f;
1199
1200         f = _http_request(URL, "HEAD", us, _http_get_proxy(flags), flags);
1201         if (f == NULL)
1202                 return (-1);
1203         fclose(f);
1204         return (0);
1205 }
1206
1207 /*
1208  * List a directory
1209  */
1210 struct url_ent *
1211 fetchListHTTP(struct url *url __unused, const char *flags __unused)
1212 {
1213         warnx("fetchListHTTP(): not implemented");
1214         return (NULL);
1215 }